AP2/ERF family transcription factors in plant abiotic stress responses.

Various abiotic stresses such as drought, high salinity, high temperature, and low temperature negatively impact plant growth and productivity of crops. Plants have adapted to respond to these stresses at the molecular, cellular, physiological, and biochemical level, enabling them to survive.

Transcriptional Regulatory Networks in Response to Abiotic Stresses in Arabidopsis and Grasses

Abiotic stresses such as drought, high salinity, and cold are common adverse environmental conditions that significantly influence plant growth and productivity worldwide. The phytohormone abscisic acid (ABA) plays an important role in physiological and developmental responses as well as in co-ordinating various stress signal transduction pathways in plants. DREBs (dehydration responsive element binding) are important plant transcription factors (TFs) that regulate the expression of many stress-inducible genes mostly in an ABA-independent manner and play a critical role in improving the abiotic stress tolerance of plants by interacting with a DRE/CRT cis-element present in the promoter region of various abiotic stress-responsive genes. This review summarizes recent studies highlighting the role of the DRE-binding family of TFs in the adaptive responses to different abiotic stresses and their structural and functional characters with emphasis on the expression and regulation of DREBs. The practical and application value of DREBs in crop improvement, such as stress tolerance engineering as well as marker-assisted selection (MAS), has also been discussed.

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Role of DREBs in regulation of abiotic stress responses in plants

Agriculture and climate change are internally correlated with each other in various aspects, as climate change is the main cause of biotic and abiotic stresses, which have adverse effects on the agriculture of a region. The land and its agriculture are being affected by climate changes in different ways, e.g., variations in annual rainfall, average temperature, heat waves, modifications in weeds, pests or microbes, global change of atmospheric CO2 or ozone level, and fluctuations in sea level. The threat of varying global climate has greatly driven the attention of scientists, as these variations are imparting negative impact on global crop production and compromising food security worldwide. According to some predicted reports, agriculture is considered the most endangered activity adversely affected by climate changes. To date, food security and ecosystem resilience are the most concerning subjects worldwide. Climate-smart agriculture is the only way to lower the negative impact of climate variations on crop adaptation, before it might affect global crop production drastically. In this review paper, we summarize the causes of climate change, stresses produced due to climate change, impacts on crops, modern breeding technologies, and biotechnological strategies to cope with climate change, in order to develop climate resilient crops. Revolutions in genetic engineering techniques can also aid in overcoming food security issues against extreme environmental conditions, by producing transgenic plants.

Impact of Climate Change on Crops Adaptation and Strategies to Tackle Its Outcome: A Review.

https://eprints.cs.univie.ac.at/3231/1/0-S1874939911001787-main.pdf

The plant heat stress transcription factor (Hsf) family: structure, function and evolution.

DREB1/CBFs and DREB2s are transcription factors that specifically interact with a cis-acting element, DRE/CRT, which is involved in the expression of genes responsive to cold and drought stress in Arabidopsis thaliana. The function of DREB1/CBFs has been precisely analyzed and it has been found to activate the expression of many genes responsive to cold stress containing a DRE/CRT sequence in their promoters. However, the regulation and function of DREB2-type transcription factors remained to be elucidated. In this research, we report the cloning of a DREB2 homolog from maize, ZmDREB2A, whose transcripts were accumulated by cold, dehydration, salt and heat stresses in maize seedlings. Unlike Arabidopsis DREB2A, ZmDREB2A produced two forms of transcripts, and quantitative real-time PCR analyses demonstrated that only the functional transcription form of ZmDREB2A was significantly induced by stresses. Moreover, the ZmDREB2A protein exhibited considerably high transactivation activity compared with DREB2A in Arabidopsis protoplasts, suggesting that protein modification is not necessary for ZmDREB2A to be active. Constitutive or stress-inducible expression of ZmDREB2A resulted in an improved drought stress tolerance in plants. Microarray analyses of transgenic plants overexpressing ZmDREB2A revealed that in addition to genes encoding late embryogenesis abundant (LEA) proteins, some genes related to heat shock and detoxification were also upregulated. Furthermore, overexpression of ZmDREB2A also enhanced thermotolerance in transgenic plants, implying that ZmDREB2A may play a dual functional role in mediating the expression of genes responsive to both water stress and heat stress.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-313X.2007.03034.x

Regulation and functional analysis of ZmDREB2A in response to drought and heat stresses in Zea mays L.

Genome-wide screening has identified 37 Al-tolerance genes in Saccharomyces cerevisiae. These genes can be roughly categorised into three groups on the basis of function, i.e., genes related to vesicle transport processes, signal transduction pathways, and protein mannosylation. The largest group is composed of genes related to vesicle transport processes; severe Al sensitivity was found in yeast strains lacking these genes. The retrograde transport of endosome-derived vesicles back to the Golgi apparatus is an important factor in determining the Al tolerance of the vesicle transport system. The PKC1-MAPK cascade signalling pathway is important in the Al tolerance of signal transduction. The lack of the gene implicated in this process leads to weakened cell wall architecture, rendering the yeast Al-sensitive. Alternatively, Al might attack the cell wall and/or plasma membrane, and, as signalling is prevented in cells devoid of the genes related to signalling processes, the cells may be unable to alleviate the damage. The genes for protein mannosylation are also associated with Al tolerance, demonstrating the importance of cell wall architecture. These genes are involved in cell integrity processes.

Masayuki Kakimoto

Papers

Regulation and functional analysis of ZmDREB2A in response to drought and heat stresses in Zea mays L.

Genome-wide screening of aluminum tolerance in Saccharomyces cerevisiae.